Light-sensitive material and method of making the same



produce a Patented July 28, 1942 LIGHT-SENSITIVE MATERIAL AND METHOD OF MAKING THE SAME Roelof Jan Hendrik Alink, Eindhoven, Netherlands, assignor, ford National Bank ford, Conn, as truste by mesne assignments, to Hartand Trust Company, Hart- No Drawing. Application May 1, 1940, Serial No.

7 Claims.

My invention relates to light-sensitive layers sensitized with a water soluble iron salt and to v a method of making the same.

The main object of my invention is to provide a simple, inexpensive and reliable method of making such layers.

A further object is to produce a material in which the light-sensitive layer isprotected from premature development and damage due to mechanical abrasion.

Further objects will appear as the description progresses.

In accordance with the invention I form a light-sensitive layer on a. support by placing a finely-divided water-soluble light-sensitive iron salt in suspension in a solution of a water-insoluble binder in a volatile organic liquid, applying this 'dispersion' in a layer on the support and removing the organic liquid by volatilization.

In one embodiment of the invention I suspend in the solution to be applied also a substance necessary for the development of the image. In

In Germany April 11, 1939 Cl. 95-6)v such cases it is necessary to employ only those combinations of iron salts and developing substances which do not react prematurely even in the presence of the organic liquid. When these precautions are taken there is considerably less danger of a premature reaction than when a v water-soluble binder, suchas gelatine, is used.

In carrying out the invention I prefer to'use those organic liquids with which it ispossible to suspension which can be readily homogenized after the suspended material has settled out during storage. Such suspensions can be made in known manner by grinding the material to be suspended with the in a ball mill.

In spite of the fact that the binder of the lightsensitive layer according to the invention is water-insoluble, the formation of the coloring material necessary for the development of the image can be readily efiected by an aqueous medium provided the layer is made in a suitable thickmess. The use of a thin layer has the advantage that it makes it possible to obtain stronger contrasts and sharper images.

The use of suspensions according to the invention has the further advantage that it is possible to obtain wide variations in the concentrations and therefore one is not limited to the solubility of the image-forming substances when obtaining a concentration necessary to secure sharply-defined contrasts.

The method according to the invention has the suspension medium advantage that it can be carried out in a simple manner and it is well adapted for use with supports of substantially water-proof material.

In order that the invention maybe clearly understood and readily carried into effect I shall describe the same in more detail by means of several specific examples.

I Example I suspension and subsequently remove the remaining solvent by'volatilization.

After exposing the sensitized material under a negative for such a long time that a basis is laid for a positive image, I rinse the same with water whereby a blue positive image is produced.

Example II I form a suspension by placing 10 grs. of finelydivided brown ferric ammonium citrate, 4 grs. o'f finely-divided silver nitrate, 1 gr. of finely-divided tartaric acid, 1 gr.

the above suspension in the manner described in Example I.. The resulting light-sensitive material is exposed in the manner ample I and rinsed with water ish-black positive image.

Example III I .form a suspension by placing 8 grs. of a finely-divided ferric ammonium oxalate, 4 grs. of finely-divided potassium ferric citrate and 1 gr. of finely-divided oxalic acid in suspension in of finely-divided citric acid' in Example I. The

Emmple IV I form a suspension by placing 8 grs. of finelydivided green ferric ammonium citrate in suspension'in 100 cos. of ethanol in which grs. of a polymerized vinyl acetic ester, known under the trade name Vinnapaas B," is dissolved. To this suspension I add 2.5 grs. of silver nitrate and 1.5 gr. of tartaric acid. An aluminium plate is provided with a layer of the above suspension and the solvent is removed in the manner described light-sensitive material is exposed in the manner described in Example I and is then rinsed with water to obtain a grayishblack positive image from the negative.

In order to protect the images formed by the methods described above from mechanical damage I prefer to apply to exposure, a layer of protective material, for example Celluloid lacquer.

Although in the above examples. I have referred to the supports of aluminium, it is possible to use supports of other metallic materials which are not affected to any appreciable extent by the substances to be used, for example silver, silver-plated metals and stainless steel.

In addition to being of metal'the supports may be of other materials such as glass, acetyl cellulose, rubber, rubber derivatives such as the product known as Pliofilm which is particularly impermeableto water, paper, etc.

Instead of using cellodammar resin as the binder I may use other substances or mixtures thereof, such as polymerized hydrocarbons, for example polysterene, polymerized unsaturated fatty acid esters, derived for example from acrylic acid and its homologues, vinyl acetic acid or the like, artificial and natural resins and gums, such as ester gum, mastic and collophony.

As organic volatile solvents in which the above binders are generally readily soluble and which can be used in carrying out the invention I may mention substances such as benzene, toluene or the like in addition to chlorinated hydrocarbons, such as trichlorethylene and carbon tetrachloride. i

Although I have described my invention with reference to specific examples and applications I do not desire to be limited thereto because obvious modifications will appear to one skilled in the art.

What I claim is:

1. In the manufacture of light-sensitive material, the steps of applying to the surface of a support a suspension of a water-soluble lightsensitive iron salt in a solution of a water-inpension of the surface thereof after soluble binding agent in a volatile organic liquid in which the iron salt is insoluble, and removing the organic liquid by volatilization.

2. In the manufacture of a light-sensitive material, the steps of applying to the surface of a support a suspension of a water-soluble lightsensitive iron salt and a substance necessary for development in a solution of a water-insoluble binding agent in a volatile organicliquid in which the iron salt and substance are insoluble, and removing the organic liquid by volatilization.

3. In the manufacture of light-sensitive material, the steps of applying to the surface of a support of substantially water-proof material a susa water-soluble light-sensitive iron salt in a solution of a water-insoluble binding agent in a volatile organic liquid in which the iron salt is insoluble, and removing the organic liquid by'volatilization.

4. A light-sensitive material made by the method of claim 1 and comprising a support, a layer of a water-insoluble binder material adheringto a surface of said support, and a watersoluble light-sensitive iron salt in a mechanically-divided state suspended in and homogeneously distributed throughout said layer.

5. A light-sensitive material made by the method of claim 1 and comprisinga support of substantially water-proof material, a layer of a water-insoluble binder material adhering to a surface of said support, and a water-soluble light-sensitive iron salt in a mechanicallydivided state suspended in and homogeneously distributed throughout said layer.

6. A light-sensitive material made by the method of claim 1 and comprising a support, a layer of a water-insoluble binder material adhering to a surface of said support, a watersoluble light-sensitive iron, salt, and a substance necessary for the development of the image, said salt and substance in a mechanically-divided state suspended in and being homogeneously distributed throughout said layer.

'7. A light-sensitive material comprising a paper support, a layer of a water-insoluble binder material adhering to a surface of said support, and a water-soluble light-sensitive iron salt in a mechanically-divided state suspended in and homogeneously distributed throughout said layer, said iron salt being readily removable from the support by agitating the material in a solvent in which the binder is soluble and the iron salt is insoluble.

ROELOF JAN HENDRIX ALINK. 

